JP2002121294A - Functionally gradient polyurethane molded product and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a functionally gradient polyurethane molded product free from an adhesive interface and continuously changing a composition of the polyurethane molded product. SOLUTION: In this functionally gradient polyurethane molded product, a composition of polyurethanes is continuously changed in one direction. The gradient polyurethane molded product is obtained by polymerizing plural kinds of urethane prepolymers having low compatibility and different in specific gravity while carrying out centrifugal separation or after carrying out centrifugal separation. In the above urethane prepolymers, polyol components as monomer components of urethane prepolymers have mutually low compatibility and are different in specific gravity. Each polyol component may be a combination of an ether type polyol with an ester type polyol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane molded article having a function inclined and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, when laminating or casting polyurethanes of different compositions, a method of laminating a plurality of polyurethanes in the form of films or sheets of different compositions is used. A method of injecting into a frame is used.

[0003] In the method of laminating polyurethanes such as films and sheets of different compositions, there is a concern that interface destruction occurs because an adhesive interface is generated. Further, it is necessary to prepare a large number of polyurethanes of different compositions, which is complicated.

In the method of injecting a polyurethane of a different composition into a mold in a semi-cured state, the steps are multi-stage, and there is a time loss required for the semi-curing. Moreover, the composition change is stepwise and discontinuous.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a functionally graded polyurethane molded article having no adhesive interface and having a continuously changing composition or function, and a method for producing the same. Another object of the present invention is to provide a functionally graded polyurethane molded article in which the composition is continuously inclined and changes from one surface portion to the other surface portion of the composite material, and a method for producing the same.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a plurality of types of urethane prepolymers having low compatibility and different specific gravities are polymerized under specific conditions. And found that a polyurethane having a tilted function can be obtained, and completed the present invention.

That is, the present invention is a functionally graded polyurethane molded article in which the composition of the polyurethane is continuously changed in one direction.

In the present invention, a functionally graded polyurethane molded article obtained by polymerizing a plurality of types of urethane prepolymers having low compatibility and different specific gravities with or after centrifugation is suitable.

In a preferred embodiment of the functionally graded polyurethane of the present invention, a plurality of types of urethane prepolymers having low compatibility and different specific gravities are obtained by mixing the polyol components as monomer components of each urethane prepolymer with each other. Are low and specific gravity is different.

In particular, in the present invention, the polyol component having low compatibility and different specific gravity is preferably a combination of an ether polyol and an ester polyol.

The present invention further provides a method of polymerizing a plurality of types of urethane prepolymers having low compatibility and different specific gravities during or after centrifugation, so that the composition of the polyurethane is continuously changed in one direction. A method for producing a functionally graded polyurethane molded article characterized by obtaining a modified functionally graded polyurethane molded article is provided.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The functionally graded polyurethane molded article of the present invention has a continuously changing polyurethane composition.
The continuous change of the composition of the polyurethane includes a continuous change of a polyol component and / or a polyisocyanate component as a monomer component of the polyurethane. In the present invention, it is preferable that at least the composition of the polyol component as the monomer component is continuously changed.

A functionally graded polyurethane molded article in which the composition of the polyurethane is continuously changed can be prepared by using a plurality of types of urethane prepolymers.
As a plurality of types of urethane prepolymers, a plurality of types of urethane prepolymers having different characteristics can be suitably used. Such properties include, for example, solubility parameters, specific gravity, and the like. In the present invention,
As the urethane prepolymer, a plurality of types of urethane prepolymers having low compatibility and different specific gravities are optimal.

[0014] Such a plurality of types of urethane prepolymers can be prepared by using monomer components having different properties as monomer components of each urethane prepolymer. For example, by using a polyol component and / or a polyisocyanate component having different properties as a polyol component and / or a polyisocyanate component of a monomer component between each urethane prepolymer, a plurality of types of urethane prepolymers can be obtained. can get. That is, at least one of the polyol component and the polyisocyanate component may be different between the monomer components of each urethane prepolymer.

In the present invention, a plurality of types of urethane prepolymers having low compatibility and different specific gravities include a polyol component as a monomer component of each urethane prepolymer.
It is preferred that they have low compatibility and different specific gravities. That is, the plurality of types of urethane prepolymers having low compatibility and different specific gravities have different compositions of the polyol component as a monomer component, respectively.
It is preferable that the polyol component has low compatibility and specific gravity is different between the polyol components of each urethane prepolymer.

It is important that the plurality of types of polyol components that differ between the monomer components of each urethane prepolymer have different properties. Specifically, as the plurality of types of polyol components, a combination of components having low compatibility between the respective types of polyol components is preferable. Further, a combination of different specific gravities is also preferable. In the present invention, as the polyol component, a polyol component having low compatibility and different specific gravity among the various types of polyol components is optimal.

It is important that a plurality of types of polyisocyanate components differing between the monomer components of each urethane prepolymer also have different characteristics, similarly to the polyol component. Specifically, as the plurality of types of polyisocyanate components, a combination of those having low compatibility between the respective types of polyisocyanate components is preferable.
Further, a combination of different specific gravities is also preferable. In the present invention, as the plurality of types of polyisocyanate components, polyisocyanate components having low compatibility and different specific gravities among the respective types of polyisocyanate components are optimal.

In the present invention, it is preferable that a plurality of types of urethane prepolymers each include a polyol component having different characteristics (particularly, low compatibility and different specific gravity) as a monomer component. In this case, the polyisocyanate component of the monomer component may be a single type of polyisocyanate component or a plurality of types of polyisocyanate components having different properties.

Examples of the polyol component include ether type polyols (eg, polyether polyols), ester type polyols (eg, polyester polyols, polycarbonate polyols), polyhydric alcohols, and castor oil.

Examples of the polyether polyol of the ether type polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and a plurality of alkylene oxides as monomer components such as ethylene oxide-propylene oxide copolymer. (Alkylene oxide-other alkylene oxide) copolymers. The polyether polyols can be used alone or as a mixture of two or more.

The ester type polyol includes polyester polyol, polycarbonate polyol and the like.

Polyester polyols include (1) condensation polymerization of polyhydric alcohol and polycarboxylic acid, (2) ring-opening polymerization of cyclic ester (lactone), (3) polyhydric alcohol, polycarboxylic acid and cyclic ester. And the like. The polyester polyols can be used alone or in combination of two or more.

In the condensation polymerization (1) of the polyester polyol, examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-tetramethylenediol, 1,5-
Pentamethylenediol, neopentyl glycol,
Examples thereof include 1,6-hexamethylenediol, 1,4-cyclohexanediol, glycerin, and trimethylolpropane. Polyhydric alcohols are used alone or in combination of two or more. Examples of the polycarboxylic acid include aliphatic dicarboxylic acids such as malonic acid, maleic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid and dodecandioic acid; 1,4-cyclohexanedicarboxylic acid Alicyclic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, and paraphenylenedicarboxylic acid;
And aromatic dicarboxylic acids such as trimellitic acid. The polycarboxylic acids can be used alone or as a mixture of two or more.

In the ring-opening polymerization (2) of the polyester polyol, examples of the cyclic ester include propiolactone, β-methyl-δ-valerolactone, and ε-caprolactone. The cyclic esters can be used alone or in combination of two or more.

In the reaction (3) using three kinds of components in the polyester polyol, as the polyhydric alcohol, the polycarboxylic acid and the cyclic ester, those exemplified above may be used alone or as a mixture of two or more kinds. it can.

The polycarbonate polyol can be obtained by (1) a reaction between a polyhydric alcohol and phosgene, and (2) a ring-opening polymerization with a cyclic carbonate (such as an alkylene carbonate). The polycarbonate polyols can be used alone or in combination of two or more.

In the reaction (1) with phosgene in the polycarbonate polyol, as the polyhydric alcohol, the polyhydric alcohols exemplified for the above-mentioned ester polyols can be used alone or in combination of two or more.

In the ring-opening polymerization (2) of the polycarbonate polyol, examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, hexamethylene carbonate and the like. The alkylene carbonates can be used alone or as a mixture of two or more.

Examples of the polyhydric alcohol of the polyol component include the polyhydric alcohols exemplified for the ester type polyol.

In the present invention, a combination of an ether polyol and an ester polyol can be suitably used as the polyol component. The ether type polyol and the ester type polyol have a number average molecular weight of at least one of 1500 or more (preferably 18 or more).
(00 or more), the compatibility may be low. In particular, the number average molecular weights of the ether type polyol and the ester type polyol are both 1500 or more (preferably 1 or more).
800 or more), the compatibility is often low. In addition, specific gravities are different for the same or similar number average molecular weight. The polyol component can be used alone or in combination of two or more.

The polyisocyanate component includes an aliphatic polyisocyanate, an alicyclic polyisocyanate, an aromatic polyisocyanate and the like. Examples of the aliphatic polyisocyanate include an aliphatic diisocyanate such as hexamethylene diisocyanate. Alicyclic polyisocyanates include isophorone diisocyanate, 4,4
Cycloaliphatic diisocyanates such as' -dicyclohexylmethane diisocyanate are included. Examples of the aromatic polyisocyanate include aromatic compounds such as diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, phenylene diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, and toluylene diisocyanate. Diisocyanates.

As the polyisocyanate component, an aromatic diisocyanate is preferred. The polyisocyanate component can be used alone or in combination of two or more.

As described above, a plurality of types of urethane prepolymers having different characteristics may be obtained by using components having different characteristics as the polyol component and / or the polyisocyanate component constituting each urethane prepolymer. Can be prepared. For example, in a plurality of types of urethane prepolymers, even if the polyisocyanate component is of the same type, the polyol component has a low compatibility and a plurality of types of polyol components having different specific gravities (e.g., , The number average molecular weight is 1
500 or more ether type polyol and number average molecular weight of 5
Combination with 00 or more ester type polyol)
Should be fine. In this case, the properties such as the specific gravity of the polyol components (for example, ether type polyols and ester type polyols) constituting the urethane prepolymer are different, and the urethane prepolymers of these monomer components are also different due to the compatibility. The characteristics differ between the two. For example, when the urethane prepolymer is centrifuged, the urethane prepolymer based on the polyol component having a higher specific gravity has a higher concentration on the outer side of the centrifuge than the urethane prepolymer based on the polyol component having a lower specific gravity, and the inner side of the centrifuge. Are separated so that the concentration becomes lower.

The functionally graded polyurethane molded article of the present invention comprises:
A plurality of types of urethane prepolymers having different properties can be obtained by polymerization with or after centrifugation.

When a plurality of types of urethane prepolymers having different properties are subjected to centrifugal separation, the urethane prepolymers are separated in one direction (for example, from the inner side (center side) to the outer side (outside) of the centrifuge). Therefore, a difference occurs in the concentration distribution, and the composition ratio or the composition of the urethane prepolymer differs as a whole. That is, the composition of the urethane prepolymer changes continuously from the inner side (center side) to the outer side (outside) of the centrifuge. By polymerizing a urethane prepolymer whose composition continuously changes in one direction, a functionally graded polyurethane molded article in which the composition of polyurethane continuously changes in one direction can be obtained.

In the present invention, the method for preparing a functionally graded polyurethane molded article is not limited to the above-mentioned preparation method, that is, a method using a urethane prepolymer prepared in advance. For example, a method of directly preparing a functionally graded polyurethane molded article from a monomer component can also be adopted.

As a method for directly preparing a functionally graded polyurethane molded article from a monomer component, for example, a plurality of types having different properties are used as at least one of a polyol component and a polyisocyanate component. These may be mixed, and the mixture may be polymerized while or after centrifugation. Specifically, for example, a mixture of a plurality of types of polyol components having low compatibility and different specific gravities, and a single type of polyisocyanate component, and while or after centrifugation, polymerized Can be prepared. In addition, it is preferable to carry out the polymerization while maintaining a state in which the distribution in which the amount of the monomer component continuously changes from the inside of the centrifuge to the outside of the centrifuge occurs.

As a method for preparing a functionally graded polyurethane molded article from a monomer component, first, a monomer component is reacted to prepare a urethane prepolymer, and then, as it is, it is subjected to polymerization with or without centrifugation. Can also be adopted. At this time, in a plurality of types of polyol components, when the number of moles of each polyol component is the same, and a single type of polyisocyanate component is used in a molar amount of about 2 times the total amount of all polyol components, both ends are reduced. A urethane prepolymer having an isocyanate group can be prepared. The urethane prepolymer having both isocyanate groups at both ends can be composed of one polyol and two polyisocyanates (the same type of polyisocyanate).
Therefore, the specific gravity of the urethane prepolymer differs depending on the type of the constituent polyol component. In addition, since a component having low compatibility is used in combination as a constituent polyol component, the prepared urethane prepolymer also has low compatibility between the various types of urethane prepolymers.

As described above, by controlling the types and mixing ratios of the polyol component and the polyisocyanate component, a functionally graded polyurethane molded article can be prepared from the monomer component.

In the present invention, low compatibility means that, for example, when a plurality of components are stirred and mixed and allowed to stand or subjected to centrifugation, the plurality of components are separated.
This means that a uniform mixing state cannot be maintained. The time required for the separation to occur is not particularly limited, but may be, for example, about 0.1 to 2 hours. In addition, the temperature at the time of separation is not particularly limited, and can be appropriately selected depending on components, polymerization conditions, and the like. For example, the temperature can be selected from a range of about 50 to 150 ° C. In the present invention, low compatibility (low compatibility) includes a state in which there is no compatibility (incompatibility).

The difference in specific gravity may be such that the difference between the larger specific gravity and the smaller specific gravity is about 1.5% of the larger specific gravity, preferably about 10%.

More specifically, the degree of low compatibility and the difference in specific gravity is such that, when both are centrifuged, continuous centrifugation from the center to the outside of the centrifuge is performed in accordance with the difference in the degree of centrifugation between the two. The composition may be changed to the extent that the composition changes.
Therefore, the separation does not have to completely occur between the components. The degree of centrifugation (centrifugal acceleration), time, temperature, and the like in centrifugation can be appropriately selected.

In the present invention, a monomer component having a plurality of active hydrogens capable of reacting with an isocyanate group may be contained as a monomer component of the polyurethane.
Examples of the monomer component include a polyamine compound.

In particular, in the present invention, a chain extender can be used in the polymerization of the urethane prepolymer. As the chain extender, a chain extender commonly used for polyurethane-based polymers can be used, and examples thereof include 3,3′-dichloro-4,4′-diaminodiphenylmethane.

Also, a polyfunctional isocyanate compound can be used as a crosslinking agent. The polyfunctional isocyanate compound may be any compound having two or more isocyanate groups (for example, an aromatic diisocyanate such as 2,4-tolylene diisocyanate; an aliphatic or alicyclic diisocyanate such as hexamethylene diisocyanate). .

In the present invention, a solvent may or may not be used when mixing or centrifuging the urethane prepolymer.

The polymerization reaction for preparing the polyurethane can be carried out by heating or heating. It is possible to advance the polycondensation reaction by raising the temperature.

The functionally graded polyurethane molded article of the present invention may contain various additives depending on the use and the like.

As described above, in the functionally graded polyurethane molded article obtained by the above method, the composition of the polyurethane changes while being continuously inclined in one direction. That is, in the polyurethane molded body, the composition of the monomer component of the polyurethane changes continuously in one direction.

If the composition of the polyurethane changes continuously in one direction, the change may increase.
It may be decreasing.

In the present invention, the continuous change means a change which is continuously inclined as a whole. Therefore, even if the change is not continuous and locally inclined, any change that is inclined as a whole is included in the continuous change in the present invention.

In the present invention, since a molded article having a shape corresponding to the internal shape of the polymerization vessel can be formed, various shapes (for example, rod shape, U-shape, irregular shape) can be obtained by changing the internal shape of the polymerization container. Etc.) can be easily produced. The method according to the invention is particularly advantageous for producing elongated shapes.

The functionally graded polyurethane molded article of the present invention comprises:
It is a blend of polymer components of different compositions, but with no adhesive interface. That is, it does not have a simple layer structure. The functionally graded polyurethane molded article of the present invention is a functionally graded polyurethane molded article in which the composition of polyurethane is inclined in one direction. The one direction is not particularly limited, but as described above, a direction from one surface portion to the other surface portion, for example, a direction from the inside of the centrifuge to the outside of the centrifuge is suitably adopted. Such a functionally graded polyurethane molded article composed of a polymer blend in which the composition of polyurethane is continuously changed has various functions and physical properties correspondingly, since the polymer composition is inclined.

The inclined functions and physical properties of the functionally graded polyurethane molded article include, for example, elasticity, toughness, tear strength, tensile strength, elongation, hardness, abrasion resistance, solvent resistance, aging resistance, and low temperature. Characteristics and the like. Functionally graded polyurethane moldings are based on polyurethanes based on ether-type polyols (such as polyether polyols),
Ester type polyol (polyester polyol, etc.)
And a functionally graded polyurethane with controlled functions and physical properties. In the present invention, the functionally graded polyurethane molded article may be an elastomer.

The functionally graded polyurethane molded article of the present invention can be attached with parts or members according to the purpose of use, if necessary. The functionally graded polyurethane molded article of the present invention can be used, for example, as a material, a member, or the like in a tube shape, a sheet shape, a bar shape, a column shape, etc., utilizing the function gradient.

According to the present invention, a functionally graded polyurethane molded article which can be easily produced without complicated steps and whose function and physical properties are continuously inclined in one direction can be prepared. It is also possible to produce functionally graded polyurethane moldings having a wide variety of shapes.

[0057]

The functionally graded polyurethane molded article of the present invention has no adhesive interface and the composition of the composite material changes continuously, so that the function and physical properties can be changed continuously in one direction. In particular, according to the present invention, an extremely wide range of functions and characteristics can be realized by appropriately selecting a combination of monomer components and the like.

[0058]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Raw materials) [Polyisocyanate component] (1) 2,4-tolylene diisocyanate: trade name "T
DI-100 ", manufactured by Nippon Polyurethane Industry Co., Ltd. (hereinafter sometimes referred to as" TDI ") [Polyol component] (Ether type polyol) (1) Polytetramethylene ether glycol (number average molecular weight: 890): trade name “PTG850SN”, manufactured by Hodogaya Chemical Industry Co., Ltd. (hereinafter sometimes referred to as “PTMG850”) (2) Polytetramethylene ether glycol (number average molecular weight: 1360): trade name “PTG1400SN”
Manufactured by Hodogaya Chemical Co., Ltd. (hereinafter referred to as “PTMG140
(3) Polytetramethylene ether glycol (number average molecular weight: 1960): trade name "PTG2000SN",
Hodogaya Chemical Industry Co., Ltd. (hereinafter referred to as “PTMG200
(4) Polytetramethylene ether glycol (number average molecular weight: 3030): trade name “PTG3000SN”,
Manufactured by Hodogaya Chemical Co., Ltd. (hereinafter referred to as “PTMG300
(May be referred to as “0”) (Ester-type polyol) (5) Polyethylene adipate glycol (number average molecular weight: 2050): trade name “Nipporan N4040”, manufactured by Nippon Polyurethane Industry Co., Ltd. (hereinafter “PEA200”)
(6) Polybutylene adipate glycol (number average molecular weight: 2020): trade name “Nipporan N4010”, manufactured by Nippon Polyurethane Industry Co., Ltd. (hereinafter, “PBA200”)
(7) Polycaprolactone glycol (number average molecular weight:
1970): trade name "PLACCEL 220N", manufactured by Daicel Chemical Industries, Ltd. (hereinafter, "PCL2000")
(8) Polyhexamethylene carbonate diol (number average molecular weight: 1990): trade name “Nipporan 980”
R ", manufactured by Nippon Polyurethane Industry Co., Ltd.
2000) (9) Polycaprolactone glycol (number average molecular weight:
990): trade name "PLACCEL 210N", manufactured by Daicel Chemical Industries, Ltd. (hereinafter sometimes referred to as "PCL1000") [Chain extender] (1) 3,3'-dichloro-4,4'-diaminodiphenylmethane : Product name “Ihara Cure Amine” manufactured by Ihara Chemical Industry Co., Ltd. (hereinafter sometimes referred to as “MOCA”)

(Compatibility of Polyol Component) The compatibility of the polyol component used as a raw material was examined.
The results shown in Tables 1 to 3 were obtained. The compatibility was determined by mixing the two components at a specific ratio at a temperature of 80 ° C., stirring, and then allowing the mixture to stand for 1 hour. Compatibility was determined on the basis of three criteria: "compatible" in which it was dissolved, "cloudy" in which the mixture was cloudy, and "separation" in which each component was separated.

[Table 1]

[Table 2]

[Table 3]

In Tables 1 to 3, numerical values (20/80, 5
0/50, 80/20) are blending ratios, and the polyol component (PTMG300) whose molecule is shown on the vertical axis in the left column.
0 to PTMG850, PC2000, etc.), and the denominator indicates the blending ratio of the polyol component (PEA2000, PBA2000, PCL2000, etc.) indicated on the horizontal axis in the upper column. Therefore, it is the ratio of the polyol component shown on the vertical axis in the left column to the polyol component shown on the horizontal axis in the upper column.

As shown in Tables 1 to 3, in the polyol component,
In the ether polyol component and the ester polyol, the number average molecular weight of at least one of the polyols is 1
If it is 500 or more, the compatibility becomes low in accordance with the mixing ratio of the two, and when both are mixed, cloudiness or phase separation occurs. In particular, if both the ether-type polyol component and the ester-type polyol have a number average molecular weight of about 2,000 or more, there is little or no relation to the mixing ratio of both, the compatibility is low, and both are mixed. If it does, it becomes cloudy or causes phase separation.

On the other hand, the number average molecular weights of both the ether type polyol component and the ester type polyol are both 140.
If it is less than 0, the two may be compatible and may not be separated by centrifugation.

(Urethane Prepolymer) The raw material polyisocyanate component and the polyol component were mixed in the combination shown in Table 4 and reacted at 85 ° C. for 2 hours to prepare a urethane prepolymer. The dehydration reaction of the polyol component was performed at 110 ° C. under reduced pressure for 2 hours.

[Table 4]

In Table 4, the mixing ratio of the polyisocyanate component and the polyol component used is represented by the molar ratio of isocyanate group (-NCO) to hydroxyl group (-OH), and "-NCO / -OH" Column. The weight ratio of isocyanate groups in the urethane prepolymer is shown in the column of “NCO%”. Further, the viscosity (cP) of the urethane prepolymer at 80 ° C. is shown in the column of “η (cP)”.

The polyisocyanate component and the polyol component of the raw materials are the ratio of the isocyanate group (-NCO) to the hydroxyl group (-OH) (-NCO / -OH).
Are used so as to be 2.0 (molar ratio), so that all or almost both terminals of the prepared urethane prepolymer are isocyanate groups.

Example 1 Urethane prepolymer "TDI / PTMG2000" preheated to 80 ° C.
And a urethane prepolymer “TDI / PEA2000” preheated to 80 ° C. were mixed at a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C. for 10 minutes, and defoamed. After defoaming, a chain extender (MOCA) heated to 120 ° C. was added at a ratio of 9.6 parts by weight based on the total weight of the urethane prepolymer, and 9 parts by weight using an agitator.
After stirring and mixing for 0 seconds, the mixture was poured into a plastic tube having an inner diameter of 13 mm. Then, the plastic tube was centrifuged (trade name "himac", manufactured by Hitachi, Ltd.).
CT6D ”) and centrifugation at a temperature of 80 ° C.
Time: 20 minutes, centrifugal acceleration: 160 × G (m / s ² )
The molding conditions were as follows. After centrifugal molding, primary curing is performed for 1 to 2 hours in an oven at 110 ° C.
Secondary curing was performed in an oven at 10 ° C. for 12 hours to obtain a tube-shaped (columnar) polyurethane molded body. The polyurethane molded article (φ13 × about 50 mm) was pale yellow and opaque.

In the present invention, G at the centrifugal acceleration
Is the standard acceleration of free fall (about 9.80 (m / s ² ),
Gravitational acceleration), for example, 160 × G (m
/ S ² ) means 160 times the gravitational acceleration.

Example 2 Example 1 was the same as Example 1 except that the centrifugal acceleration was 600 × G (m / s ² ).
In the same manner as in the above, a tube-shaped polyurethane molded body was obtained. The polyurethane molded body (φ13 x about 50 mm)
It was pale yellow and opaque.

Example 3 A tube-shaped polyurethane molded product was obtained in the same manner as in Example 1 except that the molding conditions were that the centrifugal acceleration was 2500 × G (m / s ² ). The polyurethane molded body (φ13 x about 50 mm)
It was pale yellow and opaque.

Example 4 Urethane prepolymer “TDI / PTMG2000” preheated to 80 ° C.
And a urethane prepolymer “TDI / PBA2000” preheated to 80 ° C. were mixed at a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C. for 10 minutes, and defoamed. After defoaming, a chain extender (MOCA) heated to 120 ° C. was added at a ratio of 10.0 parts by weight based on the total weight of the urethane prepolymer, and the mixture was stirred and mixed for 90 seconds using an agitator. Cast into plastic tubes. Then, the plastic tube was centrifuged (trade name "himac", manufactured by Hitachi, Ltd.).
CT6D ") and centrifugation, temperature: 80
° C, time: 20 minutes, centrifugal acceleration: 160 × G (m / s
² ) The molding was performed under the molding conditions. After centrifugal molding, primary curing is performed in an oven at 110 ° C. for 1 to 2 hours, and then the mold is removed. Secondary curing is performed in an oven at 110 ° C. for 12 hours to obtain a tube-shaped polyurethane molded body. Was. The polyurethane molded article (φ13 × about 50 mm) was pale yellow and opaque.

Example 5 Example 4 was repeated except that the centrifugal acceleration was 600 × G (m / s ² ).
In the same manner as in the above, a tube-shaped polyurethane molded body was obtained. The polyurethane molded body (φ13 x about 50 mm)
It was pale yellow and opaque.

Example 6 A tube-shaped polyurethane molded article was obtained in the same manner as in Example 4, except that the molding conditions were that the centrifugal acceleration was 2500 × G (m / s ² ). The polyurethane molded body (φ13 x about 50 mm)
It was pale yellow and opaque.

(Example 7) Urethane prepolymer "TDI / PTMG2000" preheated to 80 ° C
And a urethane prepolymer “TDI / PCL2000” preheated to 80 ° C. were mixed at a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C. for 10 minutes, and defoamed. After defoaming, a chain extender (MOCA) heated to 120 ° C. was added at a ratio of 10.0 parts by weight based on the total weight of the urethane prepolymer, and the mixture was stirred and mixed for 90 seconds using an agitator. Cast into plastic tubes. Then, the plastic tube was centrifuged (trade name "himac", manufactured by Hitachi, Ltd.).
CT6D ") and centrifugation, temperature: 80
° C, time: 20 minutes, centrifugal acceleration: 40 × G (m /
The molding was performed under the molding conditions of s ² ). After the centrifugal molding, the primary curing is performed in an oven at 110 ° C. for 1 to 2 hours, then the mold is removed, and the secondary curing is performed in an oven at 110 ° C. for 12 hours. × about 40
mm).

Example 8 Example 7 is the same as the molding condition except that the centrifugal acceleration is 160 × G (m / s ² ).
In the same manner as described above, a tube-shaped polyurethane molded product (φ1
3 × about 50 mm).

Example 9 Example 7 is the same as the molding condition except that the centrifugal acceleration is 600 × G (m / s ² ).
In the same manner as described above, a tube-shaped polyurethane molded product (φ1
3 × about 40 mm).

The polyurethane molded products obtained in Examples 7 to 9 exhibited macroscopic phase separation in the centrifugal direction. At 40 × G (m / s ² ), the state of phase separation was coarse enough to be visually observed, but the separation interface became unclear as the centrifugal acceleration increased.

(Example 10) Urethane prepolymer "TDI / PTMG3000" previously heated to 80 ° C
And a urethane prepolymer “TDI / PCL2000” preheated to 80 ° C. were mixed at a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C. for 10 minutes, and defoamed. After defoaming, a chain extender (MOCA) heated to 120 ° C. was added in a ratio of 8.3 parts by weight based on the total weight of the urethane prepolymer, and 9 parts by agitator.
After stirring and mixing for 0 seconds, the mixture was poured into a plastic tube having an inner diameter of 13 mm. Then, the plastic tube was centrifuged (trade name "himac", manufactured by Hitachi, Ltd.).
CT6D ”) and centrifugation at a temperature of 80 ° C.
Time: 20 minutes, centrifugal acceleration: 600 × G (m / s ² )
The molding conditions were as follows. After centrifugal molding, primary curing is performed for 1 to 2 hours in an oven at 110 ° C.
Secondary curing was performed in an oven at 10 ° C. for 12 hours to obtain a tube-shaped polyurethane molded body. The polyurethane molded article (φ13 × about 50 mm) was pale yellow and opaque.

(Comparative Example 1) Urethane prepolymer "TDI / PTMG2000" preheated to 80 ° C.
And a urethane prepolymer “TDI / PEA2000” preheated to 80 ° C. were mixed at a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C. for 10 minutes, and defoamed. After defoaming, a chain extender (MOCA) heated to 120 ° C. was added at a ratio of 9.6 parts by weight based on the total weight of the urethane prepolymer, and 9 parts by weight using an agitator.
After stirring and mixing for 0 seconds, the mixture was poured into a plastic tube having an inner diameter of 13 mm. Thereafter, the plastic tube was left at a temperature of 80 ° C. for a time of 20 minutes. After the standing, the primary curing is performed in an oven at 110 ° C. for 1 to 2 hours, then the mold is removed, and the secondary curing is performed in an oven at 110 ° C. for 12 hours to obtain a tube-shaped polyurethane molded product (φ13 × About 50 mm). Therefore, the polyurethane molded article according to Comparative Example 1 is basically different from the polyurethane molded articles according to Examples 1 to 3 in whether or not centrifugal separation molding is performed.

(Comparative Example 2) Urethane prepolymer "TDI / PTMG2000" preheated to 80 ° C.
And a urethane prepolymer “TDI / PBA2000” preheated to 80 ° C. were mixed at a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C. for 10 minutes, and defoamed. After defoaming, a chain extender (MOCA) heated to 120 ° C. was added at a ratio of 10.3 parts by weight based on the total weight of the urethane prepolymer, and the mixture was stirred and mixed for 90 seconds using an agitator. Cast into plastic tubes. Thereafter, the plastic tube was left at a temperature of 80 ° C. for a time of 20 minutes. After the standing, the primary curing is performed in an oven at 110 ° C. for 1 to 2 hours, then the mold is removed, and the secondary curing is performed in an oven at 110 ° C. for 12 hours to obtain a tube-shaped polyurethane molded product (φ13 × About 50 mm). Therefore, the polyurethane molded article according to Comparative Example 2 is basically different from the polyurethane molded articles according to Examples 4 to 6 in whether or not centrifugal separation molding is performed.

(Comparative Example 3) Urethane prepolymer "TDI / PTMG2000" preheated to 80 ° C
And a urethane prepolymer “TDI / PCL2000” preheated to 80 ° C. were mixed at a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C. for 10 minutes, and defoamed. After defoaming, a chain extender (MOCA) heated to 120 ° C. was added at a ratio of 10.0 parts by weight based on the total weight of the urethane prepolymer, and the mixture was stirred and mixed for 90 seconds using an agitator. Cast into plastic tubes. Thereafter, the plastic tube was left at a temperature of 80 ° C. for a time of 20 minutes. After the standing, the primary curing is performed in an oven at 110 ° C. for 1 to 2 hours, then the mold is removed, and the secondary curing is performed in an oven at 110 ° C. for 12 hours to obtain a tube-shaped polyurethane molded product (φ13 × About 50 mm). Therefore, the polyurethane molded article according to Comparative Example 3 is basically different from the polyurethane molded articles according to Examples 7 to 9 in whether or not centrifugal separation molding is performed.

(Comparative Example 4) A urethane prepolymer “TDI / PTMG850” which had been heated to 80 ° C. in advance,
Urethane prepolymer “T” preheated to 80 ° C
DI / PCL2000 "in a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C for 10 minutes, and defoamed. After defoaming, a chain extender heated to 120 ° C (MOC
A) is 14.3 relative to the total weight of the urethane prepolymer.
The mixture was added at a ratio of parts by weight, stirred and mixed for 90 seconds using an agitator, and then poured into a plastic tube having an inner diameter of 13 mm. Then, the plastic tube was centrifuged (“Himac CT6” manufactured by Hitachi, Ltd.).
D)) and centrifugation at temperature: 80 ° C., time:
The molding was performed for 20 minutes under the molding conditions of a centrifugal acceleration of 600 × G (m / s ² ). After centrifugal molding, primary curing is performed in an oven at 110 ° C for 1 to 2 hours.
Secondary curing was performed in an oven for 12 hours to obtain a tube-shaped polyurethane molded body (φ13 × about 50 mm).

(Comparative Example 5) Urethane prepolymer "TDI / PTMG1400" previously heated to 80 ° C
And a urethane prepolymer “TDI / PCL2000” preheated to 80 ° C. were mixed at a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C. for 10 minutes, and defoamed. After defoaming, a chain extender (MOCA) heated to 120 ° C. was added at a ratio of 11.5 parts by weight based on the total weight of the urethane prepolymer, and the mixture was stirred and mixed using an agitator for 90 seconds. Cast into plastic tubes. Then, the plastic tube was centrifuged (trade name "himac", manufactured by Hitachi, Ltd.).
CT6D ") and centrifugation at a temperature of 80
° C, time: 20 minutes, centrifugal acceleration: 600 × G (m / s
² ) The molding was performed under the molding conditions. After the centrifugal molding, the primary curing is performed in an oven at 110 ° C. for 1 to 2 hours, then the mold is removed, and the secondary curing is performed in an oven at 110 ° C. for 12 hours. × about 50
mm).

Comparative Example 6 A urethane prepolymer "TDI / PC2000" preheated to 80 ° C. and a urethane prepolymer “TD preheated to 80 ° C.
I / PCL2000 "was mixed at a ratio of 50/50 (parts by weight), stirred and mixed at 80 ° C for 10 minutes, and defoamed. A chain extender (MOCA) heated to 120 ° C after defoaming
Was added at a ratio of 10.1 parts by weight to the total weight of the urethane prepolymer, and the mixture was stirred and mixed for 90 seconds using an agitator, and then poured into a plastic tube having an inner diameter of 13 mm. Then, the plastic tube was centrifuged (“Himac CT6” manufactured by Hitachi, Ltd.).
D)) and centrifugation at temperature: 80 ° C., time:
The molding was performed for 20 minutes under the molding conditions of a centrifugal acceleration of 600 × G (m / s ² ). After centrifugal molding, primary curing is performed in an oven at 110 ° C for 1 to 2 hours.
Secondary curing was performed in an oven for 12 hours to obtain a tube-shaped polyurethane molded body (φ13 × about 50 mm).

Table 5 shows the compositions and molding conditions of Examples 1 to 10 and Comparative Examples 1 to 6.

[Table 5]

(Evaluation) Examples 1 to 10 and Comparative Example 1
As shown in FIG. 1, each of the tube-shaped polyurethane molded bodies according to
FT-IR measurement (ATR method (Attenuat
ed Total Reflection, attenuated total reflection spectroscopy)). The results of the FT-IR measurement are shown in FIGS. In Comparative Examples 1 to 3, FT-IR measurement was performed on the uppermost and lowermost portions of the plastic tube because centrifugation was not performed during molding.

In FIGS. 2 to 17, the horizontal axis represents the wave number (cm).
^-1 ), and the vertical axis represents transmittance (%).
FIG. 1 is a diagram showing a measurement surface of the polyurethane molded body when performing FT-IR measurement on the polyurethane molded bodies obtained in Examples and Comparative Examples.

FIGS. 2 to 4 show Embodiments 1 to 3, respectively.
FIG. 4 is a view showing a spectrum by FT-IR measurement of the polyurethane molded product according to the present invention. In FIGS. 2 to 4, the uppermost spectrum is a spectrum related to the innermost surface of the centrifuge, and the lowermost spectrum is a spectrum related to the outermost surface of the centrifuge. The spectrum below the spectrum inside the centrifuge (the spectrum at the second stage from the top) is a spectrum related to the cut surface at a position (No. 1) about 10 mm from the interior of the centrifuge, and the spectrum below it (from the top). The spectrum at the third stage) is about 10 mm
The spectrum related to the cut surface at the position (No. 2) at the position (about 20 mm from the innermost part of the centrifuge). The spectrum related to the cut surface at the position (No. 3 from the innermost part of the centrifuge) (No. 3), and the spectrum thereunder (the spectrum at the fifth stage from the top or the spectrum at the second stage from the bottom) is further about 10 mm (Approximately 40m from the innermost part of the centrifuge
7 is a spectrum related to a cut plane at a position (No. 4) of m).

FIGS. 5 to 7 show Examples 4 to 6, respectively.
FIG. 4 is a view showing a spectrum by FT-IR measurement of the polyurethane molded product according to the present invention. In FIGS. 5 to 7, the spectra from the uppermost stage to the lowermost stage show the spectra on the innermost surface of the centrifuge, each cut surface, and the outermost surface of the centrifuge, as in FIGS.

FIGS. 8 to 10 are diagrams showing the spectra of the polyurethane molded products according to Examples 7 to 9 by FT-IR measurement, respectively. In FIG. 8, the spectra from the uppermost stage to the lowermost stage show the spectra for the innermost surface of the centrifuge, each cut surface, and the outermost surface of the centrifuge, as in FIGS. 2 to 4. Since the total length is about 40 mm, There is no spectrum for the cut plane for 4. Further, each spectrum in FIG. 9 shows a spectrum on the innermost surface of the centrifuge, each cut surface, and the outermost surface of the centrifuge, as in FIGS. 2 to 4. Each spectrum in FIG. 10 shows a spectrum on the innermost surface of the centrifuge, each cut surface, and the outermost surface of the centrifuge, as in FIG. 8.

FIG. 11 is a diagram showing a spectrum of the polyurethane molded product according to Example 10 by FT-IR measurement. In FIG. 11, the spectra from the top to the bottom are the innermost surface of the centrifuge, as in FIGS.
The spectra for each cut surface and the outermost surface of the centrifuge are shown.

FIGS. 12 to 17 are diagrams showing spectra of the polyurethane molded articles according to Comparative Examples 1 to 6 by FT-IR measurement, respectively. 12 to 14, the upper spectrum is a spectrum relating to one surface of the tube, and the lower spectrum is a spectrum relating to the other surface. 15 to 17, the upper spectrum is a spectrum related to the innermost (or uppermost) surface of the centrifuge, and the lower spectrum is a spectrum related to the outermost (or lowermost) surface of the centrifuge.

From FIG. 2 to FIG. 4, the wave number is 1100 (cm ⁻¹ ).
In the vicinity, a peak due to C—O—C stretching of the ether bond (C—O—C) is observed, and the wave number is 1150 (cm ⁻¹ ).
In the vicinity, C—C of an ester bond (C—C (＝ O) —O)
A peak due to (= O) -O stretching is observed.
The intensity of these peaks changes continuously from the innermost part to the outermost part of the centrifuge. Specifically, the wave number 11
The peak related to the ether bond around 00 (cm ⁻¹ )
The strength decreases continuously from the innermost part of the centrifuge to the outermost part of the centrifuge. On the other hand, the peak of the ester bond near the wave number of 1150 (cm ^-1 ) has a continuously increasing intensity from the innermost part to the outermost part of the centrifuge.

The ether bond related to the peak observed in the IR spectrum is due to the ether bond of the ether polyol as a monomer component. Further, the ester bond related to the peak observed in the IR spectrum is:
This is due to the ester bond of the ester type polyol as a monomer component.

This means that the composition of the polyurethane changes continuously and inclining in one direction from the innermost part of the centrifuge to the outermost part of the centrifuge. Specifically, in the polyurethane molded body, the main component of the polyol component as a polyurethane monomer component continuously slopes from PTMG2000 (ether type polyol) to PEA2000 (ester type polyol) from the innermost part to the outermost part of the centrifuge. Means that it is changing. That is, it means that the composition of the polyol component as the monomer component is continuously inclined in one direction from the innermost part of the centrifuge to the outermost part thereof.

Accordingly, a functionally graded polyurethane molded article in which the composition of the polyurethane was continuously changed in one direction was obtained. This is because a plurality of types of polyol components having low compatibility and different specific gravities were used as the polyol components, so that a plurality of types of urethane prepolymers prepared in advance also had low compatibility and different specific gravities. And
Since the polymerization was carried out while centrifuging using the urethane prepolymers of a plurality of types, a functionally graded polyurethane molded product was obtained. Note that, even after centrifugation, it is possible to obtain a functionally graded polyurethane molded article by performing polymerization while maintaining the dispersed state.

As the centrifugal acceleration increases, the gradient of the composition of the polyol component as a monomer component increases from the innermost part of the centrifuge to the outermost part of the centrifuge. This means that as the centrifugal acceleration increases, the separability of the urethane prepolymer by centrifugal separation increases depending on the type of the polyol component as a monomer component.

[0098] From FIG. 5 to 7, similarly to FIG. 2 through 4, in the vicinity of a wave number of 1100 (cm ^-1), ether bond (C-O-
A peak due to C—O—C stretching of (C) was observed, and an ester bond (C—C) was observed around a wave number of 1150 (cm ⁻¹ ).
A peak due to CC (= O) -O stretching of (= O) -O) is observed. The intensity of these peaks changes continuously from the innermost part of the centrifuge to the outermost part of the centrifuge.
Further, as the centrifugal acceleration increases, the gradient of the composition of the polyol component as a monomer component increases from the innermost part of the centrifuge to the outermost part of the centrifuge.

This means that, similarly to FIGS. 2 to 4, in the polyurethane molded product, the main component of the polyol component as a polyurethane monomer component is changed from PTMG2000 (ether type polyol) to PBA2000 (Ester-type polyol). In addition, it means that the separability of the urethane prepolymer by centrifugal separation increases as the centrifugal acceleration increases.

From FIGS. 8 to 10, similar to FIGS. 2 to 4,
Near the wave number of 1100 (cm ^-1 ), an ether bond (C-O
-C), a peak due to C-O-C stretching is observed,
An ester bond (C-C) is formed around a wave number of 1150 (cm ^-1 ).
A peak due to CC (= O) -O stretching of (= O) -O) is observed. The intensity of these peaks changes continuously from the innermost part of the centrifuge to the outermost part of the centrifuge.
Further, as the centrifugal acceleration increases, the gradient of the composition of the polyol component as a monomer component increases from the innermost part of the centrifuge to the outermost part of the centrifuge. In particular, it was confirmed that at the innermost part of the centrifuge, almost or all of the polyol component as the monomer component was an ether type polyol.

This means that, similarly to FIGS. 2 to 4, in the polyurethane molded product, the main component of the polyol component as the monomer component of the polyurethane was changed from PTMG2000 (ether type polyol) to PCL2000 from the innermost part to the outermost part of the centrifuge. (Ester-type polyol).

Also, phase separation occurred macroscopically, and PTMG2000 and PCL2000 as monomer components
The reason is considered to be that the compatibility was considerably low and the specific gravity was considerably different, so that the separation properties of the urethane prepolymers related to the two by centrifugation were enhanced. Further, the separability between the urethane prepolymers by centrifugation is increasing with an increase in centrifugal acceleration.

FIG. 11 shows that, as in FIGS.
Near 100 (cm ^-1 ), an ether bond (C-O-C)
A peak due to C—O—C stretching was observed, and a wave number of 1
0.99 (cm ^-1) in the vicinity of the ester bonds (C-C (=
A peak due to C—C (＝ O) —O stretching of O) —O) is observed. The intensity of these peaks changes continuously from the innermost part of the centrifuge to the outermost part of the centrifuge.

On the other hand, from FIGS. 12 to 17, almost no difference in spectrum is observed between the innermost part (or uppermost part) of the centrifuge and the outermost part (or lowermost part) of the centrifuge. This means that the polyurethane molded body has a uniform composition from the innermost part (or uppermost part) to the outermost part (or lowermost part) of the centrifuge. Of course, the function of the polyurethane molded body is not inclined.

A urethane prepolymer based on an ether type polyol and a urethane prepolymer based on an ester type polyol are used as the polyol component of the monomer component. Even if these polyol components have low compatibility and different specific gravities, centrifugation is not necessary. If not performed, no difference can be produced in the concentration distribution of each urethane prepolymer, and it can be said that a functionally graded polyurethane molded article cannot be obtained.

Even when a urethane prepolymer based on an ether type polyol and a urethane prepolymer based on an ester type polyol are used as the polyol component of the monomer component, if the polyol component has compatibility, centrifugation is performed. It can be said that a functionally graded polyurethane molded article cannot be obtained unless the concentration distribution of each urethane prepolymer is changed even if separation is performed.

From the above results, it can be seen that the functionally graded polyurethane molded articles obtained in Examples 1 to 10 have a component material (composition) and characteristics (function) inclined in one direction.

[Brief description of the drawings]

FIG. 1 is a view showing a measurement surface of a polyurethane molded body when performing FT-IR measurement.

FIG. 2 is a diagram showing F relating to a polyurethane molded body according to Example 1.
It is a figure which shows the spectrum by T-IR measurement.

FIG. 3 is a view showing F relating to a polyurethane molded body according to Example 2.
It is a figure which shows the spectrum by T-IR measurement.

FIG. 4 is a diagram showing F related to a polyurethane molded body according to Example 3.
It is a figure which shows the spectrum by T-IR measurement.

FIG. 5 is a diagram showing F related to a polyurethane molded product according to Example 4.
It is a figure which shows the spectrum by T-IR measurement.

FIG. 6 is a view showing F relating to a polyurethane molded body according to Example 5.
It is a figure which shows the spectrum by T-IR measurement.

FIG. 7 shows F regarding the polyurethane molded product according to Example 6.
It is a figure which shows the spectrum by T-IR measurement.

FIG. 8 is a view showing F related to a polyurethane molded product according to Example 7.
It is a figure which shows the spectrum by T-IR measurement.

FIG. 9 shows F regarding the polyurethane molded product according to Example 8.
It is a figure which shows the spectrum by T-IR measurement.

FIG. 10 is a diagram showing a spectrum of the polyurethane molded product according to Example 9 by FT-IR measurement.

FIG. 11 is a view showing a spectrum of the polyurethane molded product according to Example 10 by FT-IR measurement.

FIG. 12 is a view showing a spectrum of the polyurethane molded body according to Comparative Example 1 measured by FT-IR.

FIG. 13 is a diagram showing a spectrum of the polyurethane molded product according to Comparative Example 2 measured by FT-IR.

14 is a diagram showing a spectrum of the polyurethane molded product according to Comparative Example 3 measured by FT-IR. FIG.

FIG. 15 is a diagram showing a spectrum of the polyurethane molded body according to Comparative Example 4 measured by FT-IR.

FIG. 16 is a diagram showing a spectrum of the polyurethane molded product according to Comparative Example 5 measured by FT-IR.

FIG. 17 is a diagram showing a spectrum of the polyurethane molded body according to Comparative Example 6 measured by FT-IR.

Continued on the front page F term (reference) 4F071 AA53 AA82 AF05 AG21 BB01 BB12 BB13 BC07 4J034 BA07 DA01 DB03 DB04 DF01 DF02 DF11 DF14 DG03 DG04 DG06 DG14 HA01 HA13 HA14 HC01 HC02 HC03 HC11 HC12 HC13 HC22 HC63 HC64 HC52 HC JA06 JA25 JA41 JA42 QA07 QB11 QB19 QC03

Claims (5)

[Claims] 1. A functionally graded polyurethane molded article in which the composition of the polyurethane continuously changes in one direction. 2. The functionally graded polyurethane molded article according to claim 1, which is obtained by polymerizing a plurality of types of urethane prepolymers having low compatibility and different specific gravities during or after centrifugation. 3. The urethane prepolymer of a plurality of types having low compatibility and different specific gravity has a low compatibility and a different specific gravity with a polyol component as a monomer component of each urethane prepolymer. The functionally graded polyurethane molded article according to the above. 4. The functionally graded polyurethane molded article according to claim 3, wherein the polyol component having low compatibility and different specific gravity is a combination of an ether type polyol and an ester type polyol. 5. A functional gradient in which a plurality of types of urethane prepolymers having low compatibility and different specific gravities are polymerized during or after centrifugation, and the composition of the polyurethane is continuously changed in one direction. A method for producing a functionally graded polyurethane molded article, characterized by obtaining a polyurethane molded article.